Consumable lance

Abstract

A consumable lance for introducing oxygen into molten metal. The lance is designed so that tubular oxygen passageways melt at a relatively low temperature thereby exposing refractory passageways and significantly improving the wear resistance of the lance.

I claim: 
     
       1. A consumable lance for injecting a gas into a molten metal bath, said lance comprising: (a) a longitudinal structural support assembly encased within a protective refractory covering,   (b) a plurality of longitudinal gas conduits within said refractory covering and radially spaced about said structural support assembly,   (c) a lower end portion adapted to be immersed into and consumed by said molten metal bath, and   (d) an upper end portion having a manifold system for disbursing said gas into the molten metal bath through said conduits where the longitudinal structural assembly (a) includes a closed innermost longitudinal structural member extending between the lower end portion (c) and the upper end portion (d) a series of circular spacer members spaced along the length of said closed innermost longitudinal structural member and a plurality of longitudinal bar members radially spaced about said closed innermost longitudinal structural member between adjacent gas conduits and fastened to the periphery of said circular spacer members.     
     
     
       2. The apparatus of claim 1 in which the plurality of longitudinal gas conduits (b) are tangent to the periphery of the circular spacer members of the longitudinal structural support assembly (a). 
     
     
       3. The apparatus of claim 2 in which the longitudinal gas conduits comprise sacrificial tubular members made from a material having a melting point of less than about 2,000 degrees F. 
     
     
       4. The apparatus of claim 3 in which the sacrificial members are made of copper. 
     
     
       5. The apparatus of claim 3 in which the sacrificial tubular members and bar members of the longitudinal support assembly are alternately and radially spaced about the innermost longitudinal structural member of said longitudinal support assembly. 
     
     
       6. The apparatus of claim 3 in which the sacrificial tubular members are fastened to the periphery of the circular spacer members. 
     
     
       7. The apparatus of claim 3 whereby the sacrificial tubular members melt back away from the lower portion (c) as the lance is immersed into a molten metal bath thereby creating refractory conduits or passageways through which gas is injected into said molten metal bath. 
     
     
       8. The apparatus of claim 7 whereby the molten metal bath is steel. 
     
     
       9. The apparatus of claim 7 whereby the gas is oxygen.